# Full text of "Text Book Of Mechanical Engineering"

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```Side-by-side: Late Cut-off.

669

id now expansion takes place simultaneously in H.P., L, P.,
d R, up to cut off in L. P.    Using formula (i):
Tl 4

45

•4 4-

'3

4'34   2*1

25'3

ich brings P3 up to the general hyperbola in the L. P. cylinder,
should be noted, however, that only certain proportions between
i three vessels will do this, and the curve may be either above
below the general hyperbola, as in Fig. 659. The rest of the
/-pressure diagram, Fig, 657, is easily understood, the corn-
sssion curve being a hyperbola through PL. Intermediate points
;ween P2 and P3 can, of course, be found by calculation.
Following the H. P. diagram, the steam will now be only in
nrnunication with the receiver, and must therefore be com-
rssed in H. P., Hc, and R, from P3 to P4, by formula (i):

Being cut off to exhaust before reaching P4 we assume a con-
lient point PB, and measuring, find PB = 37, or the residual
ssure we started with.

II. Compound Engine with tranks at right angles: cut off in
JP. after half stroke (at *6). This is worked out in Fig, 658, the
alt being as follows :

( H. P. = i                      -        -

Volumes-^ L. P.  - 3\$
( R.       - -45

Cut off   ...    H.P. at -45,       L, P. at '6.
After first cycle it is found that

P» » 17 "7, and PL is assumed at 18 as before,

Arriving at Pj » 62, the H. P. piston will be at the end of its

»ke, but the L. P- piston will be at mid stroke,    We therefore

ce a sudden communication with R, Lc, and half L. P., all

ch will have the same residual pressure as H, and

62 x i| 4- 177 ('45 + '3 + *2> _ _,.

*•-     •-'H+V'MT^s"    3 4

Lc   =   -3```